1. Field of the Invention
The present invention relates generally to controllers for laundry machines, and in particular to an electric laundry machine controller for automatically synthesizing, in response to a single operator selection, one of a large number of selectable laundry machine cycles or programs. The electronic laundry machine controller of this invention is particularly suitable for commercial laundering applications having unique types or classes of laundry program requirements and where it is desirable to minimize laundry program selection errors by minimizing the number of manual laundry program initiation operations required to be made by an operator of the laundry machine. Such applications may include, but are not limited to hospitals, nursing homes, hotels/motels, restaurants, cafeterias, and the like where large amounts of peculiar types of laundry must be processed.
2. Description of the Prior Art
Most laundering applications in the commercial and institutional fields require unique laundry cycles or programs for laundering various types or categories of laundry peculiar to that particular type of establishment. For example, hotels/motels may require laundry programs specifically designed for washing linens and bedspreads; whereas restaurants and cafeterias would require quite different laundry programs for washing table cloths, napkins etc. Further, there are often significant variances among establishments having the same type or class of laundry as to their respective specific laundering requirements. For example, while hotels and hospitals have the same general laundering requirements for linens, the specific requirements for the mode of execution of the basic laundry cycle or program (i.e. the duration and sequence of washing and rinse operations, the amount and type of detergents, bleaches and additives used, etc.), may vary significantly between the different respective establishments. Accordingly, for a laundry machine controller to accommodate a wide range of general classifications of commercial and institutional applications, and the varied types of laundering needs within those general classifications, it must have the capability of either providing a very large number of different laundry machine cycles or programs, or of providing a plurality of program execution variations for a number of basic classes or types of laundry cycles or programs.
Since the omission or improper execution of an operation or step of a laundry cycle may render the laundry program ineffective or even harmful to the material being laundered, the laundry machine controller must also have a high degree of program execution accuracy and must minimize the possibility of operator error being introduced into the program. This requirement becomes particularly acute in commercial and industrial laundering applications, where due to the large volume of laundry being processed, operators of the laundry machines servicing those facilities are repetitively making program selections over extended periods of time. Particularly in those applications requiring a number of different special program cycles, some of which may involve the addition of special additives to handle hard-to-remove stains or other environmental conditions, it becomes extremely important that the machine be properly activated for performing exactly the desired program. Thus, the cycle select and activation processes should be simple, and require little thought, so as to minimize operator errors due to fatigue, carelessness, or improper judgment.
Besides satisfying the above "use" requirements, a laundry machine controller for universal application in commercial and institutional environments, must be "practical" from installation, cost and service viewpoints. The practicality and use requirements would appear to be contradictory, and have not been simultaneously satisfied by prior art laundry machine controllers.
The majority of laundry machine controllers in the prior art are of mechanical or electromechanical construction. Typical of such controllers are those having a manually rotatable dial marked such that various sectors of the dial identify various distinct wash programs, formulas, or cycles. Such dials are often fixed to rotatable shafts on which a plurality of cams engage a gang of individual switches for controlling various mechanisms and subsystems within the machine. Once the dial is manually rotated to the operator-selected sector, a timer motor which drives the dial shaft and cams through that section is engaged. In this manner, the steps defined by portions of the cams in that dial sector are performed by the laundry machine. Due to the mechanical construction of such controllers, the number of easily distinguishable and unique laundry programs available with such controllers is severely limited. Alternation of an operation sequence or of entire laundry programs of such controllers is not readily performed in the field, and typically requires dismantling of the entire mechanical cam assembly. Another disadvantage of such controllers is that since the laundry programs are defined by manual selection of particular dial sectors, operator errors in program selection or in omission of one or more steps or operations from the beginning or end of a laundry program are commonly made. A number of such manual controllers have program selection dials which operate independently of the mechanism for initiating machine operation. With such controllers, it is quite possible for the operator to forget to select the proper program before actuating the laundry machine, which will result in a repeat of the program previously selected.
One electromechanical laundry machine controller of the prior art, defined in U.S. Pat. No. 3,937,981 by Nystuen et al, owned by the common assignee of this invention, offers a significant improvement over previous controllers. The Nystuen controller employs the concept of synthesizing unique laundry programs from a common set of laundry output function commands, by selecting in response to a set of program synthesis instructions various ones of the output function commands for execution. The respective "set" of program synthesis instructions are selected for activation by a single operator program selection. The output function commands and the program synthesis commands are embodied as mechanical cam elements or switch actuators on a physical surface that may comprise a removable sheet or coating for a rotatable drum. While offering a significant improvement over earlier laundry machine controllers in simplification of program selection and in improved accuracy of program execution, due to its basic electromechanical construction, the Nystuen apparatus is limited in the number of programs and in the variations thereof, which are available for execution, as an integral part of the controller, without physical alteration to the cam surface. Alternation in the field, of programs or variations thereof, requires physical replacement or alteration of the mechanical cam surface. Further, as is true with all electromechanicl controllers of the prior art, the physical cam surface and cooperatively engaging switching members are susceptible to wear and possible loss in accuracy and reliability over extended periods of use.
In attempting to overcome the inherent disadvantages of mechanical and electromechanical controllers, several controllers have appeared in the art which replace the basic motor-driven timers with an electronic controller using digital electronic control principles. Through the inherent reliability of electronic circuitry, these controllers offer significant increased reliability over the prior art electromehcanical controllers. The prior art electronic controllers, however, have not been designed to simplify operator program selection or to automatically synthesize programs in response to a single operator input command. To the contrary, the prior art electronic controllers respond to an require operator synthesis of the laundry program by requiring the operator to enter, via a plurality of manually operable switches, input commands for controlling the various laundry functions to be executed during the course of a laundry cycle or a program. Accordingly, the electronic controllers of the prior art, in their application, are particularly susceptible to human error and misuse, which is of particular concern in commercial and institutional applications where an operator is required to make many of such manual selections over extended periods of time.
The present invention overcomes the above-described disadvantages and inconveniences of prior art laundry machine controllers. The electronic laundry machine controller of the present invention offers a high degree of versatility to accommodate widely varying requirements of commercial and institutional applications, is highly reliable, maintains a high degree of accuracy in program execution, and provides heretofore unobtainable flexibility in laundry machine cycle programing while minimizing operator input error. Through the use of an electronic memory for storing laundry machine control instructions, the controller of this invention provides as an integral part of the controller proper, a large number of different laundry machine cycles or programs, capable of accommodating virtually all of the uniquely different commercial and institutional laundering requirements. Upon installation of the laundry machine controller, either at the factory, or at the user site, that set of laundry cycles or programs which exactly satisfy the peculiar laundering needs of the user, are rapidly preselected or enabled, from the large number of laundry cycles stored in the memory banks by a simple mechanical selection on several manually activated variation select switches, which are normally inaccessible to an operator of the laundry machine. Thereafter, the laundry machine operator, by a single manual operation, selects from a relatively smaller number of available selections, that laundry machine cycle or program which exactly satisfies his peculiar laundering needs. In response to the single operator selection, the laundry machine controller automatically and accurately synthesizes, by selective execution of the laundry machine control instructions stored within the electronic memory, the selected laundry machine cycle. Thus, the possibility of human error in program selection is minimized. Further, the all-electronic nature of the laundry cycle or program synthesis portion of the controller dictates that there are no moving parts to wear or become damaged over extended periods of time and use. Should the user's basic laundry needs change over time, a different set of laundry cycles or programs which more accurately accommodate the changed requirements, can rapidly be made available for selection from the larger number of laundry cycles stored in the electronic memory, by simple manually changing the relative switch positions of the variation selection switches to appropriately preselect the desired laundry cycles. Besides this simple switch selection operation, no physical changes or alterations need be made to the electronic laundry controller.